OBJECTIVE: To determine whether electrophysiologic findings of mild diabetic neuropathy in elderly patients is due to age or diabetic mellitus itself. METHOD: Electrophysiologic examination was performed in patients with diabetes mellitus and in normal control subjects over the age of 60. Electrophysiologic results of 55 diabetic neuropathy patients and the normal control subjects were compared. RESULTS: 1) Effect of age or diabetes mellitus on the electrophysiologic parameters: In normal controls over 60 years of age the motor and sensory parameter demonstrated a significant difference compared to those under 60. In diabetic patients, motor and sensory parameters demonstrated a significant difference compared to the control group. 2) Interaction of age and diabetes mellitus: Concerning the effect of age, significant differences were observed in amplitude in both motor and sensory responses. Regarding the effect of diabetes, significant differences were observed in latency or velocity in the motor and sensory nerves compared to the control group. CONCLUSION: Eletrophysiologically, prolonged latency is the result of the diabetic process, whereas decreased amplitude is thought to be due to the effect of age. In diagnosing mild diabetic neuropathy in elderly patients, we should consider the differential effects of age itself and diabetes mellitus.